打算进行其他活动后如何在recyclerview中保存复选框的值

Question

即使回收者视图打算用于其他活动，我也要保留复选框值。但是我不知道该怎么做。

意图之后，复选框的值被初始化。

这是我的回收者视图代码。

我将复选框位置发送到onBindViewHolder中的另一个活动

package com.example.teamproject.adapters;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.preference.PreferenceManager;
import android.util.Log;
import android.util.SparseBooleanArray;
import android.view.ContextMenu;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.android.volley.Response;
import com.example.teamproject.HeaderViewHolder;
import com.example.teamproject.BasicActivity;
import com.example.teamproject.MyPostActivity;
import com.example.teamproject.MyPostViewActivity;
import com.example.teamproject.MyProfileActivity;
import com.example.teamproject.PostViewActivity;
import com.example.teamproject.R;
import com.example.teamproject.models.Post;
import com.example.teamproject.myPostResult;

import java.util.ArrayList;
import java.util.logging.Handler;

public class MyPostAdapter extends RecyclerView.Adapter < MyPostAdapter.CustomViewHolder > {
    private CompoundButton.OnCheckedChangeListener onCheckedChangeListener;
    private SparseBooleanArray mSelectedItems = new SparseBooleanArray(0); //Item의 클릭 상태를 저장할 array 객체
    private ArrayList < myPostResult > arrayList;
    public static ArrayList < myPostResult > myPostArr = new ArrayList < myPostResult > ();
    private Context context;
    private final int TYPE_HEADER = 0;
    private final int TYPE_ITEM = 1;
    private final int TYPE_FOOTER = 2;
    private Button button;
    private View.OnLongClickListener onLongClickListener;
    private static final String TAG = "BAAM";
    private String[] checkarray;
    public static int position;
    private boolean isMyValueChecked;
    public CheckBox checkBox;
    public SharedPreferences sharedPreferences;

    public MyPostAdapter(ArrayList < myPostResult > arrayList, Context context) {
        this.arrayList = arrayList;
        this.context = context;
    }

    @NonNull
    @Override
    public CustomViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { //리스트뷰가 어댑터에 연결된다음에 최초로 뷰홀더만듬

        context = parent.getContext();
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_post, parent, false);
        CustomViewHolder holder = new CustomViewHolder(view);
        SharedPreferences sharedPreferences = view.getContext().getSharedPreferences("My preference", Context.MODE_PRIVATE);
        isMyValueChecked = sharedPreferences.getBoolean("checkbox", false);

        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull CustomViewHolder holder, int position) {
        //final Post post=arrayList.get(position);

        final myPostResult objincome = arrayList.get(position);

        holder.email.setText("작성자 : " + MyProfileActivity.UserNickname);
        Log.d(TAG, "POSTADATER : " + MyProfileActivity.UserNickname);
        holder.title.setText(arrayList.get(position).getBoard_title());
        holder.contents.setText(arrayList.get(position).getBoard_content());

        holder.checkBox.setText("Checkbox" + position);

        // holder.checkBox.setOnCheckedChangeListener(null);
        holder.checkBox.setChecked(objincome.isSelected());

        holder.checkBox.setTag(position);

        holder.checkBox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Integer pos = (Integer) holder.checkBox.getTag();

                Toast.makeText(context, arrayList.get(pos).getBoard_title() + "clicked!", Toast.LENGTH_SHORT).show();
                Log.d(TAG, "checkbox pos111 ;" + pos);

                if (arrayList.get(pos).isSelected()) {
                    Log.d(TAG, "checkbox pos ;" + position);
                    Toast.makeText(context, "Hihi!", Toast.LENGTH_SHORT).show();
                    Log.d(TAG, "ssibal ;" + "뒤질래?");

                    arrayList.get(pos).setSelected(false);
                } else {
                    Intent intent1 = new Intent(context, MyPostActivity.class);
                    intent1.putExtra("pos", pos);
                    context.startActivity(intent1);

                    sharedPreferences = v.getContext().getSharedPreferences("My preference", Context.MODE_PRIVATE);
                    SharedPreferences.Editor editor = sharedPreferences.edit();
                    editor.putBoolean("id", holder.checkBox.isChecked());
                    editor.commit();

                    arrayList.get(pos).setSelected(true);

                    Log.d(TAG, "checkbox pos ;" + position);

                }
            }
        });

        isMyValueChecked = sharedPreferences.getBoolean("id", false);
        holder.checkBox.setChecked(isMyValueChecked);

        myPostArr = arrayList;
    }


    @Override
    public int getItemViewType(int position) {
        if (position == 0)
            return TYPE_HEADER;
        else if (position == arrayList.size() + 1)
            return TYPE_FOOTER;
        else
            return TYPE_ITEM;
    }


    @Override
    public int getItemCount() {
        return (arrayList != null ? arrayList.size() : 0);
    }


    public class CustomViewHolder extends RecyclerView.ViewHolder {
        private TextView title;
        private TextView contents;
        private TextView email;
        CheckBox checkBox;
        Integer pos;
        public CustomViewHolder(@NonNull View ItemView) {
            super(ItemView);
            this.email = ItemView.findViewById(R.id.item_post_email);
            this.title = ItemView.findViewById(R.id.item_post_title);
            this.contents = ItemView.findViewById(R.id.item_post_contents);
            this.checkBox = ItemView.findViewById(R.id.checkBox);
            //
            itemView.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {

                    final int position = getAdapterPosition(); //현재 클릭된 리사이클러뷰의 위치 파악

                    if (position != RecyclerView.NO_POSITION) {
                        Intent intent = new Intent(context, MyPostViewActivity.class);
                        intent.putExtra("pos", position);

                        Log.d(TAG, "POSTADATER : " + MyProfileActivity.UserNickname);
                        Log.d(TAG, "POSTADATER pos : " + position);

                        context.startActivity(intent);
                    }
                }
            });
        }
    }
}

Answer 1

要保存活动状态，请参阅：

How to save an activity state using save instance state?

也许更现代的选择是查看ViewModels >>